We would like to thank Liu and Hoh1 for presenting additional information supporting our data.2 Both investigators have used different methods for insertion of human age-related maculopathy susceptibility 2 (ARMS2) cDNA into mouse genome, but aimed for the same hypothesis.

Three independent groups have now shown that overexpression of HTRA1 significantly effects the choroidal capillary, which leads to polypoidal choroidal vasculopathy (PCV) or choroidal neovascularization (CNV). Additionally, two independent groups have now shown that overexpression of ARMS2 does not have any effect in the retina.

As Liu and Hoh1 have commented, our experiment was not aimed to observe interaction of HTRA1 and ARMS2 as protein or RNA. We are now in progress to study HTRA1 promoter and regulatory elements in relation to ARMS2 gene sequence. We are also in development of a knockin mouse model of a single human HTRA1 cDNA in Rosa 26 locus using several different promoters. We hope to report this in the near future.